Albert fink



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TO ALL WHOM IT MAY CONCERN:

Beit known that I, ALBERT FINK, of Louisville, Jefferson county, Kentucky, have invented an improvement in Bridge Trusses and I do declare that the following is an exact description thereof, reference being had to the accompanying drawings, and to the letters of reference marked thereon.

The object of my improvement. is to obtain n. more durable structure than' the common wooden bridge with= out greatly increasing the cost. lIt is Well known that the lower chords of Wooden bridges are the ports of these structures irst to give Way, a comparatively small amount of decay, requiring from six to eight years of time in uncovered structures, being sufficient to'cause the failure of the lower chords of wooden bridges. It' covered so as to be protected from the elfect of the weather, the structure is in greet danger of destruction by tire or high winds; the amount of surface for the action of this ogentbeing somuch increased. In order to remedy this cause in Wooden bridges, I substitute n. Wrought-iron bottom chord for o. wooden one, and to give greater durability to the woodenportions of the bridge I-cover cach top chord with a root', and so arrange the timbers in both chordsnnd braces that there may be o. free circulation of air around them, and that any piece muy be removed and replcccd by newtimbervwithout trestling up-thc bridge or interrupting the passage of trains. I adopt the triangular system of bracing between thc two chords, both because this system best avoids evils :iris ing from the unequal expansion of a. wrought-iron bottom and wooden top chord, and because it is the system of bracing lmving the least amount of material for equal strength with other systems.

To enable others skilled in the art of bridge building to understand my invention, I n-dd the following i description:

Plaie I.

Figure l represents o general view of the improved bridge truss.

Figure 2, a a, plan of the Wrought-iron bottom chord; and

Figure 3, the wooden top chords framed together `with the top lateral bracing, both chords being corel fully proportioned vaccording to the strains; c c are the end braces, resting in the cast-iron shoe, B, which moves back and forward, :is the iron chord expands or contracts on Plate A. The ivhole structure sets on the. wall plates o o` CZ ci, tig. l, are` wrought-iron braces; e e,ff, g g, L 7L, and c c are wooden braces between top and bottom chords. I

Plate II.

Figures l, 2, 3, and 4 show the' connection of the ivooden braces with the .rrought-ironlbottoni chord. H is a. shoe casting, which receives the braces 7i 7i. The braces i Zt, fig. 2, consist of two sticks, in order that one of the sticks may be removed, (if from decay or other causes it needs replacing) while the other is holding the bridge up, thereby rendering scolfolding unnecessary. I und I, dgn 1 and 2, are castings, with lugs, N, let into the side ot' the braces h it; they are connected by the wroughtiron straps J J with the shoe casting H. A pin, M, passes through H, and connects firmly, first, the links or bars of the iron chord a a, ond, second, the braces z h to each other, through the means of the straps J J, and shoe4 costing, and, lastly, the braces and bottom chord. This connection allows the braces i i to act either as struts or ties, as the position of the moving lood may require them to do. From the pin M are suspended, by mennsrof the links T and the casting P, the floor beams U U. O is a casting, which receives the diagonal brace rods. R R are the rods which keep the floor beams spaced, and which, with the diagonal rods, form the system of horizontal bracingA of the floor of the bridge. `Plate Il, iigs. 3 and 4, shows the connection of braccsfg to cach other, and to thevrought-iron bottom chord. Under a loa-d distributed uniformly over the whole truss, the brace g has to sustain a compressive strain only, but under a moving loud it has also to sustain a small tensile strain. The connection with the shoe costing F by the rib'z i', enables the brace g to act as o tieto the extent required. The connection of the shoe casting F and the bracesfand g, and the chord o a', is made as before described.

Plata III. Figures land 2 show the connection of Wrought-iron brace d, with wooden brace e, and with iron chord a e, the same letters denoting the saine parts in figs, l ond 2. Plate lll, gs. 3 and 4:, shows the connectionv of braces g and i with upper Wooden chord Zi Zz, by means of casting Gr G, truce strap J, and pin V. Plate I und strep J form the tensile connection of 7a to b, as described in case of brace 7L und iron bottom chord a a. The rib s enables the bruce g to resist the small tensile strain which is thrown in it by n. moving loud; Any one familiar with the .VelLeStublished principles of bridge construction can proportion the various parts of this truss so that they muy resist the strains to which they :1re subjected.

I have now fully described the nature und object of my improvement. I do not claim as my invention the general arrangement of the braces, es this has long been in use for iron bridges; nor Clo I claim the use of an iron bottom chord in connection with e wooden top chord; but what I do claim as a. new und useful improvement in bridge trusses is the peculiar connection ol" wooden braces with the upper and lower chord of a bridge truss, by ineens of cust-iron shoes G, H, and F', bruce straps J J und K, :ind plates I I and I, for the purpose of forming u firm connection either for the resisting, of compressive er tensile strains, substantially as described in the above specification, Y

ALBERT FINK. vWitnesses D. W. C. ROWLAND, L. J. WAGNER. 

